Add privacy policy

### Dependency
- [ ] Bonnie writing privacy policy template. Once complete, can move this out of icebox and begin working on this issue.

### Overview
When signing up for, I was unsure of the privacy implications of entering my information into the app.

Add a privacy policy so that new and returning users can make an informed decision about entering their personal information.

### Action Items
Suggest adding at least an interim privacy policy -- broad if necessary -- so that the user can make an informed decision / feel at ease about adding their email and volunteering information.

What happens to my email, will I be added to a mailing list, will that info be shared and with whom, can I delete my info, who can see it, can I manage it, etc.
- [ ] Conduct initial research on existing privacy policies at Hack for LA
- [ ] Speak with Bonnie to investigate privacy policy
- [ ] Research with Trillium / developers re: how users can delete info / what info is stored, etc.
- [ ] Draft privacy policy
- [ ] Share with team / Bonnie for approval
- [ ] Handoff with Design / Devs (to understand screens to add privacy policy to, interactions, dev issue creation).